1. Field of the Invention
This invention relates to stepladders. More particularly, it concerns flat tread stepladders provided with tread extenders to increase the width of the first step from the top of the ladder and improve ladder safety.
2. Description of the Prior Art
Stepladders if not used properly constitute a safety hazard to homeowners and other users. As a consequence, regulations governing construction of ladders to reduce the opportunity for misuse have been issued by governmental agencies, The American National Standards institute & Underwriters Laboratories.
Persons using stepladders are frequently injured by falling from them because they were standing on the top plate or top step of the ladder. Instructions for use provided with new stepladders warn users against standing on the top plate or top step because this tends to create an unstable condition that can lead to ladder upset and injury. However, instruction for use is not sufficient to reduce this safety hazard. Many users of ladders and other equipment do not bother to read instructions. Hence, another method to mitigate injuries caused by standing on the top plate or top step of a stepladder is to construct the ladder so the user is actively discouraged from using the top plate or top step to stand on and is encouraged to use the next to top step as the maximum standing height. Another way of doing this is to widen the distance between the top plate step and the first step from the top, e.g., spacing these two members 18 inches apart. This spacing makes it difficult for the ladder user to step up onto the top plate, thereby discouraging its use to stand upon and the lower location of the top step greatly improve ladder stability in its use. However, this wider spacing creates an additional hazard. Thus, the leg of the user is not blocked by the top plate in forward movement as much as on lower steps that are more closely spaced. Consequently, it is possible for the user's foot to extend inwardly beyond the rear edge of the top step when that step has the 18 inch spacing. This permits the user to fall inward across that step.
The normal stepladder construction involves steps positioned, starting approximately twelve inches (12") from the floor and in one foot (1') intervals, to a point approximately twelve inches (12") below the stepladder top plate. However, new labeling and code requirements necessitate the placing of labels on both the top plate and top step, prohibiting their use in climbing the ladder. The maximum climbable height therefore, becomes two feet (2') less than the total height of the ladder.
In the alternate construction, the positioning of the top step eighteen inches (18") below the top plate, with the bottom step six inches (6") from the floor was allowed, together with permission for standing on the top step in this case. However, a provision is made in both codes requiring that a bar or other suitable barrier be placed across the back of the front section, between the top step and the top plate, which would prevent the user from stepping inward and consequently falling into the ladder. Quite obviously, this bar or barrier would have to be made in a manner that would prevent standing on it or of sufficient strength so that it would not bend if a careless climber did apply his weight.
An alternate provision is allowed in which a trend extension, to a point coincident with a vertical line from the leading edge of the top plate, would fit the requirement. With the top step so widened, the top plate will be able to stop the user's leg before his foot passes beyond the back edge of the top step. This invention concerns improvements in stepladders with the safety feature of a wide spaced top step combined with extra width for the step to mitigate the step-through hazard.
Of course, there are a variety of ways in which one or more steps of a stepladder may be widened. However, many of these would lead to substantially higher manufacturing costs because of increase in required number of parts, complications in ladder fabrication, etc. Hence, there exists a need in the ladder trade for a way to effectively widen the tread of steps of stepladders while maintaining good strength qualities with low manufacturing costs and also obtaining improved safety features. The present invention concerns a tread extender that not only provides the necessary extension for the safety requirement, but also involves an innovative and unique answer to the indicated existing need.
A further aspect of this invention involves the mounting of bucket rack brackets to the same common rivet of a type similar to those utilized in U.S. Pat. No. 4,187,928 and the utilization of a bucket rack unfolding from these brackets toward the rear section and resting on a rear crossbrace, which in turn achieves the same total number of rivets in the ladder.
The new ladder manufacture regulations require that means be provided for preventing the bucket rack angles or channels from projecting through the front section of a stepladder when the ladder is being folded, avoiding hitting the user in the face or body. By the arrangement provided by the present invention, this requirement is satisfied.